Unplasticized polyvinylchloride (PVC-U) profiles for the fabrication of windows and doors. Determination of the resistance to artificial weathering

2015 ◽  
Keyword(s):  
Artificial Weathering

scholarly journals Determination of some wood properties and response to weathering of Citrus limon (L.) Burm wood

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6840-6850
Author(s):  
Sırrı Sahin ◽  
Ümit Ayata ◽  
Bekir Cihad Bal ◽  
Bruno Esteves ◽  
Ahmet Can ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Wood Properties ◽  
Citrus Limon ◽  
Artificial Weathering ◽  
Dense Wood ◽  
Air Density ◽  
Screw Withdrawal

The ability of Citrus limon (L.) Burm wood to be used for flooring applications was considered in this work. Selected wood properties were determined, and the response to weathering was tested. Janka hardness, density, screw withdrawal resistance, color, glossiness, and artificial weathering (144, 288, and 432 h) were determined. The wood from Citrus limon was shown to be a dense wood with air density around 830 kg/m3 and with a high Janka hardness of 138.0 N/mm2, 120.4 N/mm2, and 115.9 N/mm2 for cross, tangential, and radial sections, respectively. This opens good perspectives to this kind of wood being used for flooring. Statistical analysis showed that both Janka hardness and screw withdrawal resistance were significantly different between surfaces. Nevertheless, the homogeneity groups showed that the main differences were between the surfaces in the longitudinal direction when compared with the transverse direction. The wood is lighter than most common woods and it is mainly yellow. After weathering, the wood became darker, redder, and yellower. Glossiness decreased in the first hours of the weathering period.

scholarly journals Artificial weathering of heat-treated pines from the Iberian peninsula

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9642-9655
Author(s):  
Bruno M. Esteves ◽  
René Herrera ◽  
Jorge Santos ◽  
Luísa Carvalho ◽  
Lina Nunes ◽  
...  
Keyword(s):  
Treated Wood ◽  
Untreated Wood ◽  
Industrial Facilities ◽  
Artificial Weathering ◽  
Class D ◽  
Heat Treated ◽  
Pinus Pinaster Ait ◽  
In The Beginning ◽  
Weathering Process

Samples from the two most common pines grown in Portugal (Pinus pinaster Ait) and Spain (Pinus radiata, D. Don) were heat-treated in industrial facilities in accordance with ThermoWood ® class D. For both species, the variation in surface properties, of untreated and heat-treated wood after artificial weathering from 75 to 750 h, is presented. The analysis included the determination of color, roughness, gloss, and wettability before exposure and after each artificial weathering period. Untreated woods became darker faster, while in heat-treated woods, lightness remained approximately constant until 750 h of artificial weathering. Both untreated and heat-treated wood became more reddish in the beginning of the weathering process, turning greener for longer exposure times. Untreated woods became yellower in the beginning, turning into blueish tones later. Heat-treated wood turned slightly yellower until 750 h of weathering. Gloss decreased for untreated wood with no significant changes in heat-treated wood. Despite the changes, the gloss of both untreated and heat-treated wood converged to similar values. Roughness increased for both untreated and heat-treated woods. Artificial weathering increased the wettability of heat-treated wood.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

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